A magnetic memory cell or device stores information by changing electrical resistance of a magnetic tunnel junction (MTJ) element. The MTJ element typically includes a thin insulating tunnel barrier layer sandwiched between a magnetically fixed layer and a magnetically free layer, forming a magnetic tunnel junction. Magnetic orientations of the fixed and free layers may be perpendicular to the growth direction, forming a perpendicular MTJ (or pMTJ) element. The pMTJ element could be formed of either a bottom pinned pMTJ element or a top pinned pMTJ element. The bottom pinned pMTJ element is formed by having the magnetically fixed layer disposed below the magnetically free layer while the top pinned pMTJ element is formed by having the fixed layer disposed above the free layer.
Spin transfer torque (STT) or spin transfer switching, uses spin-aligned (“polarized”) electrons to directly apply a torque on the MTJ layers. Specifically, when electrons flowing into a layer have to change spin direction, a torque is developed and is transferred to the nearby layer.
In order to obtain strong perpendicular magnetic anisotropy (PMA) for the fixed layer, a well-ordered crystalline orientation of the fixed layer is required. Several conventional techniques have been proposed to improve PMA for the fixed layer. However, these conventional techniques undesirably lead to reduced thermal budget and thermal endurance of the pMTJ stack.
In view of the foregoing, it is desirable to provide a memory structure with improved PMA, enhanced thermal endurance and thermal budget, as well as higher tunneling magnetoresistance (TMR) signal. Furthermore, it is also desirable to provide a method for fabricating such memory structures that is cost effective and compatible with logic processing. Also, it is desirable to provide integrated circuits and methods for fabricating integrated circuits including such memory structures. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and this background.